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Base64 Codec encodes and decodes standard, URL-safe, and MIME base64 variants. Identify mode auto-detects the variant and reveals the content type of any opaque base64 payload — JSON, JWT, image, PEM certificate, protobuf, or plain text — and parses JWT header and payload structures into typed objects ready for inspection.

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Base64 Codec

Encode, decode, and identify base64 with auto-detection

How to use

  1. Choose mode — encode (text → base64), decode (base64 → text), or identify (auto-detect content type).
  2. Select variant — standard (RFC 4648), url-safe (replaces + and / with - and _), or mime (line-broken).
  3. Paste input — For encode: text or binary. For decode/identify: any base64 variant.
  4. Run — Click Run or press Ctrl+Enter. Output shows the result, detected variant, and content type for identify mode.
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MCP / API

Call base64_codec directly from any MCP-compatible agent:

// MCP TypeScript SDK
const result = await client.callTool({
  name: "base64_codec",
  arguments: {
    "input": "...",
    "mode": "encode"
  }
});

// curl
curl -X POST https://obfus.link/mcp \
  -H "Authorization: Bearer <SPT>" \
  -H "Content-Type: application/json" \
  -d '{"method":"tools/call","params":{"name":"base64_codec","arguments":{"input":"...","mode":"encode"}}}'

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FAQ

What is the difference between standard and URL-safe base64?

Standard base64 (RFC 4648) uses A-Z, a-z, 0-9, +, /, and = for padding. URL-safe replaces + with - and / with _ so the output can appear in URL query parameters and JWT segments without percent-encoding. Padding is often omitted in URL-safe variants.

What does Identify mode detect?

JSON (parses and previews), JWT (parses header and payload into structured objects), images (detects PNG, JPEG, GIF, WebP from magic bytes), PEM certificates (RSA, EC, X.509), protobuf (byte-pattern heuristic), and plain text. The decoded preview shows the first 200 characters.

What is MIME base64?

MIME base64 (RFC 2045) is standard base64 with line breaks every 76 characters — the format required for email attachments and PEM certificate payloads. Decoders must strip line breaks before decoding; the codec handles this automatically.

Can I use this tool via the MCP API?

Yes. The tool is registered on the obfus.link MCP server at https://obfus.link/mcp. Call it from any MCP-compatible agent with a Shared Payment Token. The MCP tool name matches the snake_case slug shown in the integration snippet.